Stems (60-)100-160(-230) cm; base reddish, puberulent-glabrous. Leaves cauline, 6-20, absent from proximal 1/5 of stem at anthesis; petiole 0.5-7 cm. Leaf blade pentagonal to round, 3-9 × 3-12 cm, puberulent; ultimate lobes 3-15, width 5-60 mm; midcauline leaf lobes less than 3 times longer than wide. Inflorescences (16-)40-90(-162)-flowered; pedicel 0.5-2.5(-6.5) cm, puberulent; bracteoles 2-5 mm from flowers, reddish, linear, (3-)7-12(-15) mm, puberulent. Flowers: sepals lavender to greenish white, abaxially puberulent, lateral sepals forward pointing to form a pseudotube, 6-11 × 5-7 mm, spurs straight, slightly ascending, apically downcurved, 7-11(-14) mm; lower petal blades elevated, ± exposing stamens, 3-5 mm, clefts 1.5-2.5 mm; hairs covering adaxial surface, white or light yellow. Fruits 11-16 mm, 2.5-3.5 times longer than wide, glabrous to sparsely puberulent. Seeds unwinged; seed coat cells elongate, surfaces ± roughened.

Delphinium californicum can be confused only with D . glaucum or D . exaltatum . The three species may be separated by the abundant pubescence and early flowering date of D . californicum as compared to the other two taxa, low elevation sites of D . californicum compared to D . glaucum , and western geographic distribution of D . californicum compared to D . exaltatum .